How to Make Your Car Last Forever: Avoid Expensive Repairs, Improve Fuel Economy, Understand Your Warranty, Save Money

The previous two strokes have set everything up for the coup de gras or power stroke. The air-fuel mixture is at
maximum compression and thus volatile, assuming that the combustion chamber is tightly sealed and the
proper air-fuel mix has been delivered. All that’s needed now is ignition for the downward power stroke of the
piston to power the engine.